package 二叉树;
//https://leetcode-cn.com/problems/invert-binary-tree/
public class _226_翻转二叉树 {
    public class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;
        TreeNode() {}
        TreeNode(int val) { this.val = val; }
        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }
    public TreeNode invertTree(TreeNode root) {
        if (root == null) return null;
        //交换左右子树的位置
        TreeNode temp = root.left;
        root.left = root.right;
        root.right = temp;
        //递归交换后的左右子树
        invertTree(root.left);
        invertTree(root.right);
        //返回翻转后的树
        return root;

    }
}
